Epic simulator

Play your epic thousands of times against the calendar, the leave and the surprises, and see if the date holds. Your data stays in this browser.

Who works on this epic, and when does it start?

You need the names first, because each story gets an owner in the next step.

Epic starts

What has to be built, and how long can it take?

Days are working days of one person. A person works one story at a time, in the order of this table.

Paste from a spreadsheet

Columns: Id, Title, Owner, Best, Likely, Worst, Waits for. This replaces all stories. A header row is fine.

Which story waits for which?

Drag from the blue dot of a box to another box: the second story then waits for the first. Click an arrow to remove it. A box snaps to the grid when you drop it.

Pick the stories that must end before each story starts.

Who is away, and when?

Marked Weekend Public holiday

Futures

Nobody has past leave yet, so the dates below can be too early.

Press Run to play the futures.

85 out of 100 futures end by

The plan date

Half of the futures end by

The story to watch

The chart library did not load, so this network may block cdnjs.cloudflare.com. The numbers above and the tables below still hold.

What holds up the end

How often each story sits on the chain of waits that set the end date, out of 100 futures. The story to watch is often on that chain and has the widest range between best and worst.

Finish dates as a table

Run log

Will the date of your epic hold?

This file plays your epic thousands of times against the calendar, the leave of your people and the surprises. Then it shows the date you can trust. Five steps take you there: team, stories, arrows, leave, result.

The example in this file

Four people build the customer area of an online shop: customers sign in, pay, get refunds and invoices, and see their orders. The epic has 20 stories and starts on 2 Nov 2026.

All of it is invented. It shows the method and proves nothing about a real team.

Settings

Leave

Leave is booked untilAfter this date, nobody has booked yet. Past leave counts fromThe first day of the history you trust. Past leave counts toThe last day of that history.

Up to the booked-until date, only booked leave counts. After it, each person's past leave in the same calendar month sets the chance of a day off, in blocks of that person's usual leave length.

Sickness

A sickness starts on this many days, out of 100 working days A sickness lasts up to, in days

Type or paste the leave dates

Write dates like this: 2026-11-16 to 2026-11-27, 2026-12-24. Use this for a list from HR.

Public holidays, past and coming

Backup

This browser keeps your data, and a browser can lose it. Save a copy to a file you keep. To move to another computer, bring that file back there.

Save a copy

Downloads one JSON file with the stories, the team and the run log.

Show the JSON

Bring a copy back

This replaces everything on this page. Undo at the top brings it back. A file from the first version of the simulator also works.

Choose a JSON file

Paste the JSON instead

Start from the example

Loads the invented epic of 20 stories. Undo at the top brings your data back.